NL9201273A - METHOD FOR MANUFACTURING A POLYMER COMPOSITION CONTAINING AN ELECTRICALLY CONDUCTIVE POLYMER - Google Patents

Description

METHOD FOR MANUFACTURING ONE

POLYMER COMPOSITION CONTAINING AN ELECTRICALLY CONDUCTIVE POLYMER

The invention relates to a method of manufacturing a polymer composition containing an electrically conductive polymer, wherein the electrically conductive polymer is formed in the presence of a catalyst from polymerizable monomer units which are converted from non-polymerizable precursor monomers using a radiation source.

Such a method is described in JP-A-03-24120. According to the method described herein, a polymer composition containing non-polymerizable precursor monomers is exposed using a radiation source, whereby the precursor monomers are converted into polymerizable monomer units. Then, this polymer composition is contacted with a suitable catalyst, whereby the polymerizable monomer units polymerize into an electrically conductive polymer. With this method, a polymer composition with good electrically conductive properties and good stability of the electrically conductive properties is obtained.

The process described in JP-A-03-24120 has the drawback that the irradiation of the non-polymerizable precursor monomers and the polymerization of the polymerizable monomer units formed takes place in several successive process steps, since the catalyst can only be added after the conversion of the precursor monomers , in order to avoid undesired side reactions. As a result, the production of a polymer composition containing an electrically conductive polymer can only be achieved by means of a long-term process, which consists of several process steps. As a result, the possibilities of manufacturing articles with the known method in an economically attractive manner are limited by this lengthy process.

The object of the present invention is to provide a method in which the above-described drawbacks do not occur. The process according to the invention is characterized in that the precursor monomers have a molecular structure according to formula (I), in which

R 1 is hydrogen, -C (0) 0H, -C (0) C (0) 0H, -SO 3 H, -C (0) H, -I or -Br; R2 is hydrogen, an alkyl group (with 1-10 carbon atoms), -C (O) 0H, or a halogen; R3 is hydrogen, an alkyl group (with 1-10 carbon atoms), -C (O) 0H, or a halogen; R 4 is hydrogen, -C (0) 0H, -C (0) C (0) 0H, -SO 3 H, -C (0) H, -I or -Br; with the proviso that R1-R4 are not all hydrogen at the same time, and that R2 and R3 can both be part of a closed ring structure. For formula (I), reference is made to the formula sheet.

In the process of the invention, the catalyst can be added to the reaction mixture prior to converting the precursor monomers into polymerizable monomer units without undesired side reactions occurring. The reaction mixture can thus already contain a catalyst before exposure. This makes it possible to produce a polymer composition containing an electrically conductive polymer in a very simple and rapid manner using the method according to the invention. It is also possible with the method according to the invention to produce a polymer composition which contains an electrically conductive polymer within specifically selected areas. By means of the method according to the invention a polymer composition with electrically conductive paths is obtained. The obtained polymer composition, which contains an electrically conductive polymer, can for instance be used as (semi-) conductive material, as electrode material and as material on which an electrically conductive pattern is applied, such as, for example, Printed Circuit Boards.

Preferably, the precursor monomer is pyrrole-2-carboxylic acid. The synthesis of this precursor monomer is described in J. Am. Pharm. Assoc. £ 5,509 (1956). In the precursor monomer of formula I, all combinations of X, R1, R2, R3 and R4 are possible. The R1 and R4 groups can be thermally or photochemically eliminated to form a pyrrole, thiophene or furan monomer substituted or not substituted at the R2 and / or R3 position. The monomer formed is polymerizable, and can polymerize via the R1 and R4 position. The groups R2 and R3 can be the same or different. The groups R2 and R3 can also both form part of a closed ring structure. A suitable example of such a precursor monomer is 3,4- (alkylene-vic-dioxy-) thiophene-2,5-dicarboxylic acid (see Tetrahedron 1967, vol. 23, p. 2137 ff.).

The catalyst which can be used in the process according to the invention is selected, for example, from the group of inorganic acids, such as, for example, hydrochloric acid, sulfuric acid, chlorosulfonic acid and nitric acid,

Lewis acids, such as, for example, compounds containing positive ions of iron, aluminum, tin, titanium, zirconium, chromium, manganese, cobalt, copper, molybdenum, tungsten, ruthenium, nickel, palladium and / or platinum, and a halogen, a sulfate a nitrate, an aryl sulfonate, such as, for example, p-toluenesulfonate and p-dodecylbenzene sulfonate, and / or an acetylacetonate. Other suitable catalysts are, for example, ozone, diazonium salts, organic catalysts, such as, for example, benzoquinone, and persulfates, such as ammonium persulfate, sodium persulfate and potassium persulfate. In certain polymerization reactions

Ziegler-Natta catalysts and K2Cr207 working well. Good active catalysts are, for example, FeCl3, FeBr3, FeCl3.6H20, CuCl2.2H20, CuSO4, Fe (NO3) 3.9H20, K3Fe (CN) 6 /

Cu (NO 3) 2, Fe (ClO 4) 3, 9H 2 O, Fe 2 (SO 4) 3.5H 2 O, and (C 5 H 5) 2 Fe + FeCl 4 -. If desired, a mixture of different catalysts can be used. Particularly effective catalysts are iron (III) chloride and copper (II) chloride. The catalyst is usually added in a molar ratio to the precursor monomer, which is between 100 and 10; 1. Preferably, this ratio is between 1: 3 and 3: 1.

If desired, a matrix polymer is added to the polymer composition according to the invention. For this purpose, a matrix polymer can for instance be dissolved in the polymer composition, but it is also possible to impregnate, for example, a molded part with the polymer composition.

Depending on the requirements of the polymer composition, for example with regard to the mechanical properties, in principle any polymer can be selected. Thermoplastic polymers are preferred in view of the processability, but thermosetting polymers, such as resins and binders, are also very suitable as matrix polymer for certain applications. Suitable matrix polymers are, for example, polyvinyl chloride or copolymers of vinyl chloride and other vinyl monomers, polyvinylidene fluoride or copolymers of vinylidene fluoride and other vinyl monomers, polystyrene or copolymers of styrene and other monomers, such as, for example, maleic anhydride and maleimide, polyacrylates or copolymers of an acrylates polyvinyl carbazole, polyolefins, such as, for example, polyethylene, ultra high molecular weight polyethylene (UHMWPE), and polypropylene, polyvinyl acetate, polyvinyl alcohol, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, polyesters, such as, for example, polyethylene terephthalide, polyethylene terimethyl ether, polycarbonate polyamides, polyamideimides, polyethylene oxide, polybutadiene rubbers, alkyd resins, polyurethanes, acrylate resins, and the like. If desired, a mixture of multiple polymers can be used as a matrix polymer. In a special embodiment of the method according to the invention, the reaction mixture is applied to a substrate / for instance in the form of a coating, after which the precursor monomers are released.

Preferably, the matrix polymer used is porous. The porosity of the matrix polymer used is usually greater than 30%, preferably greater than 50%, and more preferably greater than 65%. Suitable moldings which can be used, for example, are films, foils, fibers, plates and other objects. Porous films containing a thermoplastic matrix polymer are described, for example, in EP-A-105629, EP-A-309136, EP-A-288021 and WO-A-86/02282. Films containing a polyolefin as a matrix polymer are described, for example, in EP-A-193318.

Films containing an ultra high molecular weight polyethylene polymer as a matrix polymer are described, for example, in EP-A-378279 and EP-A-163424.

The desired weight ratio between the amount of matrix polymer and the amount of electrically conductive polymer in the polymer composition according to the invention is a result of the optimization between the various desired properties, such as, for example, the desired conductive properties on the one hand and the desired mechanical properties on the other. High concentrations of matrix polymer have an adverse effect on the conductivity in the final polymer composition, while low concentrations of matrix polymer may have an adverse effect on the desired mechanical properties. The weight ratio between the amount of matrix polymer and the amount of electrically conductive polymer in the polymer composition of the invention can vary within wide limits. Usually this ratio is between 1:99 and 99: 1, preferably between 1:15 and 15: 1.

The various components to obtain the polymer composition according to the invention can be mixed in the usual ways known to the person skilled in the art. Preference is given to methods in which the precursor monomers and the catalyst are dissolved in a suitable solvent, after which the matrix polymer is added if desired. The solvent is often selected from the group of water, aromatic compounds, such as, for example, benzene, toluene and xylene, alcohols, such as, for example, methanol and ethanol, hydrocarbons, such as, for example, pentane and hexane, ethers, such as, for example, dioxane, diethyl ether, ethyl methyl ether and tetrahydrofuran, ketones such as, for example, acetone, diethyl ketone, and methyl ethyl ketone, halogenated compounds, such as, for example, CHCl3, CH2 Cl2, and carbon tetrachloride, esters, such as, for example, ethyl formate and ethyl acetate, and compounds such as acetonitrile, nitromethane, dimethyl sulfoxide, dimethyl formamide, triethyl phosphate, dimethyl acetate. Mixtures of several solvents can also be used. In some cases, the precursor monomer itself can be used as a solvent.

The non-polymerizable precursor monomers present in the polymer composition are converted into polymerizable monomer units by irradiation using a radiation source, or a light source. Radiation sources which can be used in the process of the invention emit radiation, which contains sufficient power to convert the non-polymerizable precursor monomers into polymerizable monomer units. Lasers are particularly suitable for use as a radiation source, but lamps, such as IR lamps, UV lamps and VIS lamps, are also good alternatives. In a special embodiment, sunlight is used.

The polymer composition can be irradiated with a solid radiation source, with portions of the polymer composition optionally covered with a mask, or with a moving (writing) radiation source. When a focused radiation beam is desired, for example when an electrically conductive path is written, the emitted radiation can be bundled using a converging lens system. When a wide radiation beam is desired, for example when working with the aid of a mask, the emitted radiation can be spread using a diverging lens system. When a fixed radiation source is used, a high power radiation source is usually used. When a moving, or writing, radiation source is used, a low power radiation source is usually used. The writing speed at which the non-polymerizable precursor monomers present in the polymer composition are converted into polymerizable monomer units is usually between 5 and 300 mm / s; preferably between 15 and 200 mm / s.

Examples of suitable radiation sources are gas lasers, such as, for example, CO2 lasers and N2 lasers, Excimer lasers, Argonion lasers, Kryptonion lasers, diode laser, copper vapor lasers, titanium sapphire lasers, Dye lasers and Neodymium Yttrium Aluminum Garnet lasers (Nd: YAG lasers). Suitable radiation sources can emit a continuous radiation beam, but it is also possible for a pulsating radiation beam to be used.

CO2 lasers to be used usually emit light with a wavelength between 9 μκι and 11 μm, preferably around 10.6 μm (infrared).

Nd to be used: YAG lasers emit light with a wavelength of 1064 nm; preferably, frequency doubling is used, whereby the wavelength of the emitted light is 532 nm. The pulse frequency usually varies between 1 Hz and 10 kHz, preferably between 3 and 6 kHz. The diameter of the parallel light beam usually varies between 0.01 and 0.5 mm; preferably between 0.02 and 0.15 mm. The current applied is usually between 10 and 25 A; preferably between 10 and 18 A; more preferably between 12 and 15 A. The energy density of the light beam used is usually between 0.10 kWatt / cm2 and 1 MWatt / cm2.

Excimer lasers to be used contain, for example, Xenon fluoride gas or Xenon chloride gas, and emit light with a wavelength of, for example, 351 nm or 308 nm.

Argon lasers to be used emit light with wavelengths of, for example, 514.5 nm, 502 nm, 496.5 nm, 488 nm, 476.5 nm and / or 458 nm, at a power of, for example, 0.1 to 10 Watt. Preferably the power is 1-5 Watt.

Lasers with good adjustability of the laser parameters, such as, for example, the laser power and the wavelength, are preferred, as they can be optimally adapted to the specific method.

After the method according to the invention, any catalyst residues and other low molecular weight components can be removed by extraction and / or evaporation. If desired, unexposed parts of the polymer composition can be removed in such a manner. The extraction methods are well known.

The polymer composition according to the invention may, if desired, still contain up to 60% by weight of fillers and / or antioxidants. Examples of fillers are talc, reinforcing fibers, conductive fibers, light-absorbing additives, pigments, kaolin, wollastonite and glass.

Depending on the precursor monomer used, the electrically conductive properties of the polymer composition can be brought to a higher level, by means of an (oxidative or reductive) doping step, using the known doping techniques and reagents. These are mentioned, for example, in the 'Handbook of conducting polymers' (T.A. Skotheim, Marcel Dekker Inc., New York, USA (1986)).

The invention is illustrated by the following examples without being limited thereto.

The conductive properties of the polymer composition in the given examples were measured according to the so-called two-point method. This method has been described by H.H. Wieder in Laboratory Notes on Electrical and Galvanomagnetic Measurements, Elsevier, New York, 1979. Resistance is determined using this method.

Example I

A porous ultra high molecular weight polyethylene (UHMWPE) film with a thickness of 30 µm (length * width = 5 * 5 cm2; porosity 85%) was impregnated with a solution of 250 mgram pyrrole-2-carboxylic acid and 700 mgram FeCl3 in tetrahydrofuran (THF ). A mask was put on this film. The whole was then exposed with an Argonion laser (Spectra Physics 2025 Argonion laser; all-lines mode; power 2 Watt), which was equipped with a diverging lens, for 3 seconds.

After irradiation, an electrically conductive pattern corresponding to the mask was formed on the film. This pattern was colored dark. Resistance was measured after extraction with acetone: 2500 Ohm. The formation of the electrically conductive polymer had occurred throughout the thickness of the film.

Examples II-V

A porous ultra high molecular weight polyethylene (UHMWPE) film with a thickness of 30 µm (length * width = 5 * 5 cm2; porosity 85%) was impregnated with a solution of 250 mgram pyrrole-2-carboxylic acid and 700 mgram FeCl3 in tetrahydrofuran (THF ).

Subsequently, the obtained film was exposed with a writing Argonion laser (Spectra Physics 2025 Argonion laser; writing speed 1 cm / second; applied power 4.5 mW; continuous beam), which was set to a certain defined wavelength: example wavelength [nm] II 514.5 III 496 IV 488 V 476.5

During the exposure, the laser beam was focused to a diameter of approximately 30μπι. After exposure, an electrically conductive track was formed on the film with a width of approximately πμπι. After extraction with acetone, the resistance was measured: 30 kOhm. The formation of the electrically conductive polymer had occurred almost through the entire thickness of the film.

Example VI

A porous ultra high molecular weight polyethylene (UHMWPE) film with a thickness of 30μπι (length * width = 5 * 5 cm2; porosity 85%) was impregnated with a solution of 250 mgram pyrrole-2-carboxylic acid and 700 mgram FeCl3 in tetrahydrofuran (THF ).

Then, the obtained film was exposed with a writing Nd: YAG laser (Haas laser Gretag 6411; polished, 2 SHG, Q-switched, wavelength 532 nm, writing speed 100 mm / s). After exposure, an electrically conductive trace was formed on the film. Resistance was measured after extraction with acetone: 200 kOhm. The formation of the electrically conductive polymer had occurred on the surface of the film.

Example VII

A porous ultra high molecular weight polyethylene (UHMWPE) film with a thickness of 30μπι (length * width -50 * 50 cm2; porosity 85%) was impregnated with a solution of 25 grams of pyrrole-2-carboxylic acid and 70 grams of FeCl3 in tetrahydrofuran (THF ).

Then, the obtained film was exposed with an IR lamp for 30 minutes. After extraction with acetone, the resistance was measured: 500 ohms.

Example VIII

250 mg of pyrrol-2-carboxylic acid and 700 mg of FeCl 3 were dissolved in 3.5 µl THF. 400 mg of alkyd resin (high fatty acid content, viscosity 50 poise) were added to this solution. The resulting mixture was coated on a polyethylene terephthalate (PET) film.

The coating was then exposed with a NdtYAG laser (Haas laser Gretag 6411; polished, 2 SHG, Q-switched, wavelength 532 nm, writing speed 100 mm / s). After exposure, an electrically conductive trace was formed on the film. Resistance was measured after extraction with acetone: 150 kOhm.

Comparative experiment

A porous ultra high molecular weight polyethylene (UHMWPE) film with a thickness of 30μπι (length * width * 50 * 50 cm2; porosity 85%) was impregnated with a solution of 25 grams of pyrrole-2-carboxylic acid and 70 grams of FeCl3 in tetrahydrofuran (THF ).

After drying, the film so impregnated was stored at a temperature of 20 ° C for 4 hours. Then the film was extracted with acetone. After analysis, the acetone was found to contain quantitatively the amounts of pyrrole-2-carboxylic acid and FeCl3 used.

The examples show that a polymer composition containing an electrically conductive polymer is manufactured in a very rapid manner, so that the process can be carried out in an economically attractive manner.

The comparative experiment shows that with the method according to the invention the catalyst can be added to the reaction mixture even before the polymer composition is exposed, without undesired side reactions occurring.

Claims (13)

A method of manufacturing a polymer composition containing an electrically conductive polymer, wherein the electrically conductive polymer is formed in the presence of a catalyst from polymerizable monomer units which are converted from non-polymerizable precursor monomers by means of a light source, characterized in that the precursor monomers have a structure according to formula (I), wherein

R 1 is hydrogen, -C (0) 0H, -C (0) C (0) 0H, -SO 3 H, -C (0) H, -I or -Br; R2 is hydrogen, an alkyl group (with 1-10 carbon atoms), -C (O) 0H, or a halogen; R3 is hydrogen, an alkyl group (with 1-10 carbon atoms), --C (O) 0H, or a halogen; R 4 is hydrogen, -C (0) 0H, -C (0) C (0) 0H, -SO 3h, -C (0) h, -i or -Br; with the proviso that R1-R4 are not all hydrogen at the same time, and that R2 and R3 can both be part of a closed ring structure. 2. Process according to claim 1, characterized in that the precursor monomers are pyrrole-2-carboxylic acid. A method according to claim 1 or 2, characterized in that the polymer composition also contains a matrix polymer. A method according to any one of claims 1 to 3, characterized in that the polymer composition is exposed with a solid light source, the parts of the polymer composition which are not to be exposed being covered with a mask. Method according to claim 4, characterized in that the light source is a gas laser. Method according to any one of claims 1-3, characterized in that the polymer composition is exposed with a moving light source. Method according to claim 6, characterized in that the light source is a pulsating laser or a continuous laser. A method according to claim 7, characterized in that the pulsating laser is a Neodymium Yttrium Aluminum Garnet laser, an Excimer laser, an Argonion laser, or a Kryptonion laser. Method according to any one of claims 6-8, characterized in that the diameter of the light beam emitted by the light source is between 0.01 and 0.5 mm. Method according to any one of claims 6-9, characterized in that the writing speed of the moving light source is 15-200 mm / s. A method according to any one of claims 1-10, characterized in that the polymer composition undergoes a doping step after exposure. 12. Polymer composition containing electrically conductive paths. A composition containing precursor monomers having a structure according to formula (I), wherein

R 1 is hydrogen, -C (0) 0H, -C (0) C (0) 0H, -SO 3 H, -C (0) H, -I or -Br; R2 is hydrogen, an alkyl group (with 1-10 carbon atoms), -C (O) 0H, or a halogen; R3 is hydrogen, an alkyl group (with 1-10 carbon atoms), -C (O) 0H, or a halogen; R 4 is hydrogen, -C (0) 0H, -C (0) C (0) 0H, -SO 3 H, -C (0) H, -I or -Br; with the proviso that R1-R4 are not all hydrogen at the same time, and that R2 and R3 can both be part of a closed ring structure. 13. Method as substantially described and illustrated by the examples.